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Photos showing typical surface breaks on the western segment of the 2010 Yushu earthquake rupture (see Fig. 2 for locations). Arrows point to the trace of the surface rupture zone. (a) A straight rupture sinistrally cutting into the grass clumps in a swampy area. View to the west. (b) NE-striking en echelon extensional fissures at the east section of the west segment on the southern shore of Longbao Lake. View to the west. (c) Sinistral offset of the grass cluster about 40 cm from the rupture, with a view to the west. (d) Surface rupture that consists of en echelon fissures, pressure ridges, and sinistrally displaced the car tracks, by about 20 cm. Inset at the upper right corner is a close-up view of the offset. View to the west. (e) Eastward view of the discontinuous rupture of the 2010 earthquake following the preexisting fault scarp. (f) View of discontinuous ground cracks at the west termination of the surface rupture south of Jielong. View to the east. The color version of this figure is available only in the electronic edition.
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On the morning of 14 April 2010, the M-s 7.1 Yushu earthquake struck the eastern Tibet Plateau and an M-s 6.3 aftershock followed west-southwest of the mainshock epicenter one and a half hours later. The Yushu earthquake occurred on the northwestern continuation of the Ganzi-Xianshuihe fault zone and reactivated two segments of the fault. Ruptures...
Citations
... The locking depth is an important parameter for the inversion process. The locking depth is uniformly taken as 15 km by considering seismic relocation results (The Working Group of M7 2012), the depth of modern destructive earthquakes (Li et al. 2012;Yi et al. 2017), and the optimal locking depth of major faults in the Sichuan-Yunnan region (Wang et al. 2011(Wang et al. , 2022Zhao et al. 2020). Figure 6 shows the strikeslip and compressive/tensile rates of the major faults in the study area. ...
Quantitative analysis of the slip rate of active faults and their seismic parameters is important for seismic hazard analysis. In this study, we first construct an elastic block model to obtain the slip rate of boundary faults based on the distribution characteristics of active faults, seismicity, and global navigation satellite system (GNSS) observations in Sichuan–Yunnan, China. Then, the long-term seismic risks of the boundary faults are quantitatively evaluated based on the principle of seismic moment balance. The Sichuan–Yunnan region can be divided into 17 relatively independent and stable subblocks. There is clear zoning in the distribution and mechanisms of boundary fault movement and deformation. The boundary faults exhibit an alternating dextral–sinistral–dextral–sinistral strike-slip pattern from northeast to southwest. Among these boundary faults, the Xianshuihe–Xiaojiang fault zone has a high sinistral strike-slip rate, and the Jinshajiang fault plays an important role in accommodating the movement and deformation of the subblocks in the Chuandian block. The dextral strike-slip rate is approximately 10 mm/yr, which is diffusely transferred to the secondary boundary faults in the Chuandian block. Comparison of the rates of moment accumulation and release reveals that the southern segment of the Xiaojiang fault, the Longriba fault, the Daliangshan fault, and the Yuanmou fault exhibit significant moment deficits, with corresponding moment magnitudes exceeding Mw 7.5. More attention should be given to the strong earthquake risks of these faults. The Xianshuihe–Xiaojiang, Jiali–Lancangjiang, and Red River faults, which are arc shaped, dominate the regional deformation and determine the motion and deformation model of the subblocks and secondary boundary faults within the Chuandian block and the area southwest of the Red River fault.
... N, 96.60° E) was located at an elevation of 4300 m with an epicenter intensity of IX (Liu et al., 2011). The seismogenic fault is the Ganzi-Yushu fault, which is part of the northwestern continuation of the Ganzi-Xianshuihe fault zone ( Figure 15A; Li et al., 2012b). During the earthquake, the seismogenic fault caused a strike-slip surface rupture with a lateral offset of up to 1.8 m, a strike of 300°, and an extension of approximately 65 km ( Figure 15B; Zhang et al., 2010b). ...
... During the earthquake, the seismogenic fault caused a strike-slip surface rupture with a lateral offset of up to 1.8 m, a strike of 300°, and an extension of approximately 65 km ( Figure 15B; Zhang et al., 2010b). The event resulted in at least 2698 deaths, 270 missing persons, and more than 12,000 injuries (Li et al., 2012b). ...
... Large-scale intracontinental strike-slip faults have played important roles in the accommodation of tectonic deformation that results from the collision between the Indian Plate and Eurasian Plate since 45 ± 5 Ma [34,[39][40][41][42][43][44], although their geodynamics is still debated. In particular, the XFZ constantly releases strain energy with an average left-lateral slip rate of 8-10 mm/year or less [38,[45][46][47][48][49][50][51] or with a temporal and spatial variable slip rate [52][53][54] and has experienced multiple cycles of stress accumulation and release since the late Quaternary (Figures 1 and 2). Although many scientific achievements along the XFZ have been attained by geologists in recent years, the active tectonics and seismogenic behavior along the whole portion of the XFZ remain disputed [35,36,39,[55][56][57][58][59][60][61][62]. ...
... The 2022 (M 6.8) Luding earthquake occurred on the Moxi segment of the XFZ, which is a distinguished NW-SEtrending seismogenic structure with strong earthquakes within the Tibetan Plateau and has triggered at least 60 strong earthquakes (M ≥ 6) since 1500 CE [29,33,38,39,45,48,49,51,57,60,[62][63][64] (Figure 1). The XFZ includes many subsections from southeast to northwest; they are named the Zemuhe Fault Zone, the Anninghe Fault Zone (AFZ), the Xianshuihe Fault Zone (XFZ, in the narrow sense), the Ganzi-Yushu Fault Zone (GYFZ), and the Dangjiang Fault Zone (DFZ) to the northwest ( Figure 1). ...
... Figure 1b is illustrated by the black dashed line) obviously shows that three regional strike-slip faults, the JCFZ, XFZ, and EKLFZ from southwest to northeast, may constitute the main boundary fractures of different active blocks within the plateau interior and have direct control over regional topographic variations. In addition, both the spatial distribution images of destructive earthquakes (Ms ≥ 4.7) and the active tectonic studies in recent years show that these regional faults have undergone strong tectonic deformation since the late Quaternary [1,33,38,48,51,62]. ...
The 2022 (M 6.8) Luding earthquake on the Xianshuihe Fault Zone (XFZ) caused severe casualties and property losses, and surface deformation and damage of which is crucial for studying the earthquake hazard assessment. However, few intensive scientific understanding has obtained to date because of widespread coronavirus transmission, strong vegetation coverage, and post-earthquake paralyzed traffic. By integrating high-resolution satellite images, large-scale geomorphic mapping, and UAV surveys, we constrain coseismic fractures and ruptures along an NW-SE-trending surface deformation zone, with discontinuous geomorphic scarps, en echelon cracks, and bulges concentrated in the areas of Yanzigou, Moxi, Menghugang, and Xingfu villages near the epicenter. Field observation also shows that the zone extends nearly parallel to the pre-existing XFZ with a length of ∼35 km with variable widths and a maximum vertical displacement of ∼100 ± 10 cm. The earthquake-induced surface coseismic effects, such as landslides, rock falls, and collapses, caused damage to the area. The amplification effect of the topography and the improper aseismic design and poor constructions may be responsible for the spatial distribution of MM Intensity IX, which is larger than other previous earthquakes that occurred in the surrounding area with a similar tectonic setting.
... mm/yr from Zhou et al. (1996) and 7±3 mm/yr from Wu et al. (2017), and more recently 6.3±1.9 mm/yr by Yu et al. (2022). The Yushu fault is only known to be active after the 2010 M s 7.1 earthquake that produced a ∼70 km long surface rupture (Li et al., 2012). The geological slip rate of the Yushu fault was measured to be 6.8-8.2 mm/yr (Huang et al., 2019). ...
... As one of the most seismically active fault systems within the continents, the Yushu-Ganzi-Xianshuihe fault system has experienced a series of moderate-to-strong earthquakes since 1700 (Allen et al., 1991;Wen et al., 2003Wen et al., , 2008. Fig. 7b shows the major earthquakes in written records and their approximate rupture extents since 1700 (Li et al., 2012;Wen et al., 2003Wen et al., , 2008Yu et al., 2022). Many studies, e.g. ...
The 900-km-long Yushu-Ganzi-Xianshuihe fault system that separates the Bayan Har and Qiangtang/Chuandian blocks is a primary tectonic structure in central eastern Tibet. Being one of the world's most seismically active fault systems, it hosted 12 M>7 earthquakes since the 18th century, and its future seismic risk has been the subject of extensive research over the past two decades. Previous studies have suggested that the western segment of the fault system differs largely from its eastern segment in strain accumulation and release, but the origin of such difference remains unknown. Here we use Sentinel-1 data to produce a complete map of present-day deformation for the entire fault system, in order to explore the along-strike variation in fault slip behaviour. Based on the InSAR deformation map, we solve for fault kinematic parameters including slip rate, locking depth and dip angle using a Bayesian Markov Chain Monte Carlo inversion approach. Slip rate on the Dangjiang-Yushu-Ganzi fault is consistently ∼5–6 mm/yr, only half of that on the Xianshuihe fault. This rate difference originates from nonuniform deformation mechanism within the Bayan Har block, with the western part of the block deforming more rigidly than the eastern part. Both historical and modern earthquake catalogues show that the western fault segment has only recorded M>7 earthquakes whereas the eastern segment has seen many small-to-moderate ruptures in addition to large earthquakes. These observations imply that the western fault segment may be more structurally mature than the eastern segment, which agrees with the long-term fault propagation as indicated by geochronological data and fault geometrical complexities. We calculate the seismic moment deficits along the fault system and find that several segments, e.g. the Dangjiang fault and the Manigange segment of the Ganzi fault, have accumulated a large seismic moment (equates to an Mw>7 earthquake) since the last major event.
... It is bounded by the NWW-trending major left-lateral strike-slip Kunlun and SN-trending Minjiang faults in the north, to the southwest by the Ganzi-Yushu-Xianshuihe fault system separating the Qiang Tang Block to the south, and to the southeast by the NE-trending Longmenshan thrust, which also bounds the eastern margin of the Tibetan Plateau (Figure 1a). Since the end of the twentieth century, eight large earthquakes (M ≥ 7) have occurred surrounding the Bayan Har Block: the 1997 Mw 7.5 Manyi earthquake (on the Ganzi-Yushu-Xianshuihe Fault) [13], the 2001 Mw 7.8 Kunlun earthquake (on the Kunlun Fault) [14], the 2008 Mw 7.9 Wenchuan earthquake (on the Longmenshan Fault) [15,16], the 2010 Mw 6.9 Yushu earthquake (on the Yushu-Xianshuihe Fault) [17], the 2013 Mw 6.6 Lushan earthquake (on the Longmenshan Fault) [18], and the 2017 Mw 6.9 Jiuzhaigou earthquake (on the Mingjiang Fault) [19]. The focal mechanism of these earthquakes implies that the Bayan Har Block is currently moving to the southeast relative to the South China block ( Figure 1a). ...
A magnitude (Mw) 7.4 Maduo earthquake occurred on 22 May 2021 in the northern Qinghai-Tibet Plateau, with predominantly left-lateral strike-slip faulting and a component of normal faulting within the Bayan Har Block. The co-seismic surface rupture extended in a NWW direction for ~160 km with a complicated geometry along a poorly known young fault: the Jiangcuo Fault. The main surface rupture propagated bilaterally from the epicenter and terminated eastward in horsetail splays. The main rupture can be divided into five segments with two rupture gaps. Field surveys and detailed mapping revealed that the co-seismic surface ruptures were characterized by a series of left-lateral offsets, en echelon tensional cracks and fissures, compressional mole tracks, and widespread sand liquefication. The observed co-seismic left-lateral displacements ranged from 0.2 m to ~2.6 m, while the vertical displacements ranged from 0.1 m to ~1.5 m, much lower than the InSAR inverse slip maximum of 2–6 m. Based on the comprehensive analysis of the causative fault geometry and the tectonic structure of the northern Bayan Har Block, this study suggests that the multiple NWW trending sub-faults, including the Jiangcuo Fault, developed from the East Kunlun fault northeast of the Bayan Har Block could be regarded as the sub-faults of the East Kunlun Fault system, constituting a broad and dispersive northern boundary of the Block, controlling the inner strain distribution and deformation.
... Broadly speaking, the XFZ (in the broad sense) is a well-known NW-SE trending seismogenic structure within the Tibetan Plateau, and more than 60 earthquakes with magnitudes greater than 6.0 have occurred since CE 1500 because of repeated left-lateral slippage along the structure (Allen et al., 1991;Lin et al., 2002;Wen et al., 2003;Wang et al., 2007;Wen et al., 2008;Li et al., 2012) (Figure 1). The structure is composed of many subsections from southeast to northwest, including the Zemuhe Fault Zone (ZFZ), the Anninghe Fault Zone (AFZ), the Xianshuihe Fault Zone (XFZ, in the narrow sense), and the Ganzi-Yushu Fault Zone (GYFZ) (Figure 1). ...
... The basement in this study area consists mainly of Triassic limestone, sandstone, mudstone, and shale with volcanic rocks (Lin et al., 2011), while the Cenozoic strata are dominated by Paleogene purple coarse-grained sediments, Neogene purple finegrained lacustrine sediments, and Quaternary unconsolidated deposits. Previous seismological studies have revealed that modern and historical destructive earthquakes, together with paleoearthquakes along the faults, have ruptured these branches of the GYFZ with variable co-seismic surface rupture sizes and distinctive geomorphic features (Zhou et al., 1997;Lin et al., 2011;Li et al., 2012). ...
... Unless otherwise specified, all earthquake records and active faults were collected from the China Earthquake Networks Center (2019), Gu, (1983), the Editorial Board of Annals of Sichuan (Zhou, et al., 1997;Lin et al., 2011), while the red star represents the epicenter of the 2010 Ms 7.1 Yushu earthquake (modified from Lin et al., 2011;Li et al., 2012). The beach ball at the bottom right represents the focal-mechanism solution (Li et al., 2012), which indicates that the 2010 Ms 7.1 Yushu earthquake is mainly sinistral shear rupture. ...
The role of large-scale strike-slip faults in high-elevation areas in absorbing the strain resulting from plate convergence has yet to be scientifically understood. The Dang Jiang Fault (DJF), as the NW continuation of the Xianshuihe Fault Zone (XFZ) in the central Qinghai-Tibetan Plateau, may provide an excellent testing ground for this question, given its high slip rate, sparse vegetative cover, minimal modification, and possible relationship with the CE 1738 Dangjiang destructive earthquake. However, co-seismic surface ruptures and seismotectonics remain in dispute because of inconvenient transportation and lack of oxygen at high altitudes. Thus, field investigations are conducted here to determine co-seismic surface ruptures. The newly synthesized data from geologic observations, historical record reviews, geomorphic mapping, trench logging, and sample dating indicate that the CE 1738 Dangjiang earthquake produced an ∼100 km-long surface rupture that includes offsets of gullies, linear scarps and troughs, sag ponds, en echelon fractures, and pressure ridges. The magnitude is re-estimated as M 7.6, with average and maximum strike-slip displacements of ∼2.1 ± 0.1 m and ∼3.5 ± 0.1 m, respectively. The DJF has undergone multiple seismic faulting events, and the linear fitting surface displacement rate in the Holocene is ∼6.3 ± 1.9 mm/yr with a 95% confidence interval. This study implies that the seismic hazard of the DJF cannot be underestimated given that its elapsed time is close to or beyond the recurrence interval of major earthquakes and that the oblique convergence of the Qiangtang Block might be accommodated by the clockwise rotation of the block through repeated left-lateral strike-slip movements along the southern boundary of the Bayan Har Block.
... The M w 6.9 Yushu earthquake occurred on 14 April 2010 about 30 km northwest of Yushu town, Tibet, China (Fig. 1), causing 2678 fatalities and more than 12,000 injuries (Li et al. 2012). The mainshock registered as M s 7.1 and M w 6.9 by the China Earthquake Networks Centre (CENC) and the U.S. Geological Survey (USGS), with a focal depth around 14 km, respectively. ...
... The triggered shaking lasted for about 16 s and consisted of two sub-events . Field investigation revealed a * 70-km left-lateral strike-slip surface rupture with three left-step offsets (Lin et al. 2011;Li et al. 2012). The surface rupture, with coseismic displacements of 0.3-3.2 ...
... The surface rupture, with coseismic displacements of 0.3-3.2 m, was localized in a zone about 50 m wide along a pre-existing surface trace of the Yushu fault Li et al. 2012), the northeastern segment of the Ganzi-Yushu fault system. Seismic waveform inversion suggests that the M w 6.9 earthquake nucleated near the Longbo stepover basin in the west, propagated unilaterally eastward, and terminated at the east segment margin of the Yushu fault . ...
The Mw 6.9 Yushu earthquake occurred on 14 April 2010, rupturing the Yushu segment of the previously mapped left-lateral strike-slip Ganzi-Yushu fault, southeastern Tibet. We constructed eight temporary GPS benchmarks across the faulting belt in a quick mode within 1 week after the mainshock. The newly constructed benchmarks and seven pre-existing ones were observed in campaign mode, with each session lasting for 3 consecutive days. The entire observations spanned a period of 250 days until the end of 2010, capturing early post-seismic transients induced by the Yushu earthquake. The GPS-derived post-seismic motions generally had the same orientations as the coseismic displacements. The post-seismic displacement time series are modeled with a logarithmic function, obtaining a characteristic decay time scale of 6.7 ± 0.2 days. Using the GPS site displacements, we investigated the possible mechanism of the stress relaxation process. The estimated surface displacements due to possible poroelastic rebound did not agree with the observed displacements. Multiple tests with various viscoelastic models, including the Burgers model, standard linear solid rheology and Maxwell relaxation model, show that the viscoelastic deformation in the early post-seismic phase was possibly insignificant. Thus afterslip was deemed dominant in the process of stress relaxation. We identified that the afterslip was primarily located at the northwestern and southeastern flanks of coseismic slip distribution, anti-correlated with the coseismic slip spatially. Moreover, we found that the time-dependent afterslip decays rapidly with time. With moments released by the aftershocks and afterslip taken into account, we derived a new recurrence period of 124–452 years for an M 7 class earthquake similar to the Yushu earthquake in the Ganzi-Yushu fault. The newly derived recurrence interval benefits the seismic hazard assessment in the southeastern Tibetan Plateau.
... Ever since the 2010 Yushu earthquake occurred, many workers have explored the geometry of seismogenic fault, fault surface rupture distribution, and kinematic rupture history based on globally distributed broadband seismic recordings, field investigations, and/or regional geodetic observational data (Zhang et al. 2010a;Chen et al. 2010b;Zhang et al. 2010b;Zhang et al. 2010a;Yao et al. 2010;Li et al. 2011;Pan et al. 2011;Wu et al. 2011;Lin et al. 2011;Rao et al. 2011;Tobita et al. 2011;Zha et al. 2011;Li et al. 2012;Wang and Mori 2012;Yokota et al. 2012;Sun et al. 2013;Wen et al. 2013;Zhang et al. 2014). The main feature of coseismic rupture models for the 2010 Yushu earthquake is generally the same, although there were different ways to acquire the data. ...
... Immediately after the Yushu mainshock, many research units such as China Geological Survey and China Earthquake Administration organized numerous workers to carry out an extensive scientific field investigation, and published a large number of papers (mostly in Chinese) (e.g., Chen et al. 2010b;Zhang et al. 2010b;Zhang et al. 2010a;Pan et al. 2011;Wu et al. 2011;Lin et al. 2011;Rao et al. 2011;Li et al. 2012), which provided a rough outline on fault geometry and surface ruptures. From the results, we could know that different fault geometries, different surface ruptures and different coseismic displacements are from different authors, due to inconvenient geography, difficult access and high altitude. ...
... On the other hand, the realistic geometry of the seismogenic fault responsible for the 2010 Yushu earthquake is not known exactly. For example, planar fault is obtained according to inversion of seismic waves (Zhang et al. 2010c;Xu et al. 2011), and the traces of the surface rupture in the Yushu earthquake are different from each other by means of field observations (Chen et al. 2010b;Zhang et al. 2010b;Pan et al. 2011;Wu et al. 2011;Rao et al. 2011;Li et al. 2012) . Hence, it is difficult to ascertain the accurate fault geometry for the Yushu event, although the fault geometry is the simplest and the most obvious observable characteristic feature relating to the fault. ...
The moderate-size 2010 Yushu earthquake (Mw 6.9) caused severe seismic damage around the source region which is situated on the sparsely populated hinterland of the Tibetan Plateau. But until now the mechanisms have not been well understood. To this end, we constructed the model to simulate the fault spontaneous rupture propagation, in which the realistic fault with a curved bend is imbedded. Our modeling results show that the special fault geometry controlled the rupture behavior, which encouraged rupture propagation speed transition from subshear to supershear with the speed of 5.17 km/s larger than the local shear wave velocity. Moreover, calculation results demonstrated that strong ground motion acceleration was greatly intensified by supershear ruptures, leading to widespread destruction. This may be the main reason why serious earthquake damage happened in the Yushu earthquake. In particular, we can see from numerous numerical experiments that rupture styles will be different if geometries of fault are varied. It is confirmed that it is the special geometry of the seismogenic fault of the Yushu mainshock produced grave seismic hazard. Thus, deeply investigating fault geometry will be helpful to better understand seismic source process and seismic hazard assessment.
Key Points
Curved bend in the seismogenic fault for the 2010 Yushu earthquake encouraged the supershear rupture transition.
Strong ground motion acceleration was greatly intensified by supershear ruptures.
Special geometry of the fault of the Yushu mainshock lead to seriouos seismic damage.
... As a result, the state of stress is high in the Tibetan plateau because of crustal shortening along its eastern edge, which in turn increases the earthquake hazard, particularly in western China. This process gives rise to five of the most active fault zones in eastern Tibet: the Yushu-Ganzi-Xianshuihe fault zone, Haiyuan, Altyn Tagh, Kunlun, and Karakorum faults (Li et al., 2012). The deformation of the Tibetan plateau caused by the continuing indentation of India into Eurasia was the cause of great earthquakes: the 1997 Manyi earthquake (M s 7.9), the 2001 Kunlunshan earthquake (M s 8.1), the 2008 Wenchuan earthquake (M s 8.0), and the 2010 Yushu earthquake (M s 7.1). ...
Empirical relationships between the macroseismic intensity and the ground-motion parameters (peak ground acceleration [PGA], peak ground velocity [PGV]) for western China are derived in this study. A strong ground-motion database including 34 moderate to large earthquakes is used along with the corresponding modified Mercalli intensity (MMI) information inferred from isoseismal maps and earthquake damage reports. A weighted least-squares regression with analytic hierarchy process (AHP) is used to find the following simple relationships between MMI and PGA or PGV with V ≤ I ≤ IX: MMI = 3:311 log PGA - 0:354, MMI = 3:356 log PGV + 3:315. These new relationships are significantly different from the Liu et al. (1980) correlations, which have been used in the Chinese macroseismic seismic intensity scale (CMSIS). The proposed simple relationships are then compared with similar equations developed from other regions. Comparison confirms that such relationships should be regional-dependent because the frequency content of ground motions exhibits local properties. To quantify the regional variations to the global relationships from Caprio et al. (2015), regional correction factors (RCFs) for western China are obtained by the proposed simple relationships. We also refined predictive relationships that include M s and epicentral distance as independent variables.
... Along the central segment, the Xianshuihe fault, three earthquakes of Ms >7.3 have occurred since 1923 (Allen et al., 1991;Wen, 2000), producing surface rupture up to 110 km long and coseismic offsets up to 5.5 m. The NW segment, consisting of the Yushu/Batang and Ganzi faults, seems less active, even though several large-magnitude earthquakes have occurred since the late 1800s (Table 1), including the 2010 Mw 6.9 Yushu earthquake (star #3 in Fig. 1A), which produced 70 km of surface rupture along the Yushu fault, with coseismic offsets of 1-2 m (e.g., Li et al., 2012;Zhang, 2013). ...
... Following the Yushu earthquake, the Yushu fault has been extensively studied using interferometric synthetic aperture radar (InSAR) methods (e.g., Liu et al., 2011;Tobita et al., 2011; and field investigations (e.g., Lin et al., 2011;Li et al., 2012), giving a broad estimation of the presentday slip rate of 2-10 mm/yr. Late Quaternary horizontal slip rates along the Ganzi fault (Table 2) also show large uncertainties, between 3 and 14 mm/yr (e.g., Zhou et al., 1996;Wen et al., 2003;Xu et al., 2003;Shi et al., 2016;colored dots in Fig. 1D) using offset-age reconstructions (with 14 C, optically stimulated luminescence [OSL], or thermoluminescence [TL] dating), and 9-15 mm/yr using paleoseismology . ...
The left-lateral strike-slip Xianshuihe fault system (XFS) located in eastern Tibet is one of the most tectonically active intra-continental fault system in China, if not in the world, along which more than 20 M>6.5 earthquakes occurred since 1700, including the 2010 Mw6.9 Yushu earthquake. It is therefore essential to precisely determine its slip-rate, which remains poorly constrained at all timescales, in order to evaluate regional earthquake hazard. Here, we focus on the NW segment of the XFS, the Ganzi fault. We studied three sites where the active Ganzi fault cuts and left-laterally offsets moraine crests and fan edges. We constrained left-lateral offsets using LiDAR and kinematic GPS, and used cosmogenic dating to determine the abandonment age of the offset surfaces. We found that the slip-rate remains constant along the entire Ganzi fault (~300 km) at 6-8 mm/yr at the late Quaternary timescale, consistent with geodetic (InSAR and GPS) as well as with geologic slip-rates (6.2-6.6 mm/yr since ~12.6 Ma). This implies that the Manigango segment of the Ganzi fault could potentially produce a M7.6 earthquake in the near future. While the XFS propagated from west to east, the fact that the Ganzi fault's long-term slip-rate is similar to that of the Xianshuihe fault to the SE suggests that the onset of the XFS at ~13 Ma marks a major transition in tectonic regime in SE Tibet.
